[Reconstructive orbital surgery]. / Rekonstruktive Orbitachirurgie.

BACKGROUND: In complex orbital reconstructions ideal positioning of the bony buttress and surrounding soft tissue is a prerequisite for an aesthetic and functional result. The use of computer-assisted surgery can support the surgeon before and during the reconstruction procedure and facilitate quality control processes. This is illustrated using three clinical examples. MATERIAL AND METHODS: The areas of interest (bony defect areas, surrounding tissues) are segmented in a 3D image series. In most cases, the contralateral non-affected side can serve as the reference in virtual reconstruction. The virtual model obtained can now be used for the manufacturing of patient specific models and implants, as well as for intraoperative navigation or direct quality control with the use of intraoperative cone beam computed tomography (CBCT). RESULTS: For the reconstruction of primary and secondary traumatic defects as well as for congenital malformations or neoplastic diseases, the presented workflow can be used. Preoperative virtual visualization, patient specific reconstruction and direct quality control using intraoperative CBCT ensure that the preoperatively planned result can be achieved. Together with the interplay of hard and soft tissue the best possible results can be achieved. CONCLUSION: Computer-assisted surgery has been continuously further developed over the last two decades and is currently used in the clinical routine. Patient specific implants in combination with the use of direct intraoperative quality control facilitate the reconstruction of complex orbital injuries and defects and enable the ideal reconstruction from both aesthetic and functional aspects.

Restoration of Anterior Dental Erosion with a Combination of Veneers and Crowns: A 3-Year Case Report.

This report describes the conservative management of a 40-year-old female patient with smooth, eroded facial enamel affecting her maxillary anterior and some posterior teeth. Using conventional enamel bonding, pressed leucite-reinforced laminate veneers were used to restore the length, contour, and esthetics of the maxillary right canine, as well as of the right lateral and both central incisors; at the same time, it was necessary to restore the maxillary left lateral incisor, canine, and first premolar of the same quadrant with all-ceramic crowns of the same material. The patient has been followed for 3 years and demonstrates a good esthetic outcome with no shade discrepancy between the two types of restoration. Apparently, the tooth structure, though eroded, was able to provide an adequate bonding substrate for these adhesive restorations.

The influence of pressure changes on endodontically treated teeth during simulated dives.

AIM: To measure and evaluate pressure changes in the pulp chambers of extracted teeth exposed to hyperbaric conditions during root canal treatment. METHODOLOGY: A pressure sensor was inserted and sealed into the pulp chambers of extracted human molars (n = 6). The teeth were subjected to simulated dives to 4.5 bar in a diving chamber. During the simulated ascents and descents, the pressure within the pulp chamber was measured, and the difference between the pressure inside the pulp chamber and the pressure in the diving chamber was calculated. Each tooth underwent two dives with an intact pulp chamber, with a calcium hydroxide dressing, after root canal filling, and after adhesive sealing of the pulp chamber floor with a composite. Differences were analyzed statistically (P < 0.05) using one-way analysis of variance (anova). RESULTS: There were no significant pressure differences in teeth with an intact pulp chamber and teeth with a calcium hydroxide dressing. After root filling, however, the increase in pressure inside the pulp chamber was significantly lower (P < 0.05) than that in the diving chamber. After adhesive sealing of the pulp chamber floor with a composite, the pressure inside the pulp chamber was significantly lower (P < 0.05) than the pressure in the diving chamber. CONCLUSIONS: In root canal treatment, canal orifices should be sealed with an adhesively bonded composite filling before a dive. The use of a calcium hydroxide dressing after root canal preparation does not disqualify patients from diving.

[Reconstruction of complex midfacial defects with individualized titanium implants]. / Rekonstruktion komplexer Mittelgesichtsdefekte durch individualisierte Titanimplantate.

BACKGROUND: Loss of hard and soft tissue structures of the midface due to resection or trauma is associated with substancial functional and aesthetic deficits. Besides reconstruction of bony contours for preservation of orbit position and facial symmetry, reconstruction often requires simultaneous transplantation of soft tissue flaps for separation of nasal and oral cavities and refilling of soft tissue volume deficits. PATIENTS AND METHODS: A well-established procedure of our institution will be demonstrated in 10 exemplary patients, in which titanium meshes are customized for individual defect situations using computer-assisted techniques in combination with soft tissue transfer if required. RESULTS: According to our experience, this procedure provides satisfactory results in functional as well as in aesthetic respects. Especially in patients with loss of bony structures of the orbit and preservation of orbital contents, this procedure forms optimal preconditions for prevention of enophthalmos and diplopia by preservation of the original orbital volume. CONCLUSION: Individualized titanium implants should be used more frequently in clinical routine for reconstruction of complex midfacial defects.

Atomic force microscopy for the characterisation of pinning effects of seawater micro-droplets in n-decane on a calcite surface.

HYPOTHESIS: Roughness is an important parameter in applications where wetting needs to be characterized. Micro-computed tomography is commonly used to characterize wetting in porous media but the main limitation of this approach is the incapacity to identify nanoscale roughness. Atomic force microscopy, AFM, however, has been used to characterize the topography of surfaces down to the molecular scale. Here we investigate the potential of using AFM to characterize wetting behavior at the nanoscale. EXPERIMENTS: Droplets of water on cleaved calcite under decane were imaged using quantitative imaging QI atomic force microscopy where a force-distance curve is obtained at every pixel. FINDINGS: When the AFM tip passed through the water droplet surface, an attraction was observed due to capillary effects, such that the thickness of the water film was estimated and hence the profile of the droplet obtained. This enables parameters such as the contact angle and contact angle distribution to be obtained at a nanometer scale. The contact angles around the 3-phase contact line are found to be quasi-symmetrically distributed between 10-30°. A correlation between the height profile of the surface and contact angle distribution demonstrates a quasi-proportional relationship between roughness on the calcite surface and contact angle.

Virtual planning, simultaneous dental implantation and CAD/CAM plate fixation: a paradigm change in maxillofacial reconstruction.

Prosthetic rehabilitation in patients undergoing reconstructive surgery using vascularized free flaps is challenging, and functional rehabilitation of the patient with a fixed prosthesis is rare. Virtually planned maxillofacial reconstruction including simultaneous dental implantation according to the prosthodontic ideal position of the implants could further enhance dental rehabilitation. The data of 21 patients undergoing fibula free flap reconstructive surgery with CAD/CAM patient-specific reconstruction plates during the years 2015-2018 were analysed, including the applicability of the virtual plan, flap survival, duration of surgery, ischemia time, simultaneous dental implantation, implant exposure, and postoperative complications. The virtual plan could be translated to surgery in all cases. In total, 76 dental implants were simultaneously placed during primary reconstruction in the 21 patients. For 38.1% of these patients, the implants could be uncovered in secondary surgery; the mean duration until exposure was 7.6 months. The implant survival rate was 97.4% (74/76). Wound infection requiring a secondary intervention occurred in 23.8% of patients during follow-up. Virtually planned reconstruction with a fibula free flap, simultaneous dental implantation, and CAD/CAM plates allows early and functional dental rehabilitation. A dental workflow should be integrated into the virtual planning, and prosthetically favourable implant positions should determine the position of the fibula segments.

Precision of 30 guided implants in complex tumour situations.

Implant born prosthetic rehabilitation of tumour patients can be difficult to perform. Challenges in treating such patients include disrupted anatomy with limited mouth opening due to previous ablative surgery as well as free-flaps or simple bone grafts, adjuvant therapy such as radiotherapy and, in general, poorer general health. Combining classical knowledge of ideal prosthesis placement and current virtual planning possibilities the positioning and in consequence the survival of dental implants can be optimised. Since prosthetic rehabilitation has a positive effect on the patients' quality of life and general health, we propose performing such surgeries as early as possible. All patients at our institution receiving pre-planned guided implant reconstruction and postoperative evaluation with Cone Beam Computed Tomography (CBCT) between 2015 and 2018 were evaluated for inclusion. Eight patients with a total of 30 implants met the inclusion criteria. The planned implant position was compared to the outcome position by fusing the two and deviations in entry-point position, apex-position, angular deviation and depth error were recorded. The mean (SD) discrepancy at entry-point was 2.28 (1.45) mm and 2.89 (1.53) mm at the apex, respectively. Mean (SD) angulation discrepancy was 9.5˚ (4.13˚) and the mean (SD) depth deviation was 1.52 (0.86) mm. Our results demonstrate the feasibility of pre-planned implant placement in challenging clinical situations and that only few concessions have to be made for precision.

Relationship between wetting and capillary pressure in a crude oil/brine/rock system: From nano-scale to core-scale.

HYPOTHESIS: The wetting behaviour is a key property of a porous medium that controls hydraulic conductivity in multiphase flow. While many porous materials, such as hydrocarbon reservoir rocks, are initially wetted by the aqueous phase, surface active components within the non-wetting phase can alter the wetting state of the solid. Close to the saturation endpoints wetting phase fluid films of nanometre thickness impact the wetting alteration process. The properties of these films depend on the chemical characteristics of the system. Here we demonstrate that surface texture can be equally important and introduce a novel workflow to characterize the wetting state of a porous medium. EXPERIMENTS: We investigated the formation of fluid films along a rock surface imaged with atomic force microscopy using ζ-potential measurements and a computational model for drainage. The results were compared to spontaneous imbibition test to link sub-pore-scale and core-scale wetting characteristics of the rock. FINDINGS: The results show a dependency between surface coverage by oil, which controls the wetting alteration, and the macroscopic wetting response. The surface-area coverage is dependent on the capillary pressure applied during primary drainage. Close to the saturation endpoint, where the change in saturation was minor, the oil-solid contact changed more than 80%.

Comparison of two beta-tricalcium phosphate composite grafts used for reconstruction of mandibular critical size bone defects.

OBJECTIVE: The aim was to compare osseointegration of blood perfused beta-tricalcium phosphate cylinders (beta-TCPB) with similar composites that were additionally loaded with cancellous bone and bone marrow (beta-TCPB/BM/CB) for mandibular reconstruction. METHODS: Twelve German Black-Headed sheep with an average weight of 72.5 +/- 10 kg underwent segmental resection of the right hemi-mandible. The animals that were assigned to group A (n = 6) were reconstructed using beta-TCPB while the sheep that were assigned to group B received beta-TCPB/BM/CB grafts. Tissue quality was histologically assessed and bone-, scaffold-, cartilage- and fibrous-tissue area were estimated using semiautomated histomorphometrical software. RESULTS: Composite grafts that were loaded with bone marrow and cancellous bone (beta-TCPB/BM/CB) exhibited significant (p<0.01) higher amounts of bone formation than beta-TCPB. The patients that were assigned to group B achieved defect union and a high grade of bone maturation. Residual ceramic remnants were rare and disconnected. Bone maturity within group A was inferior and none of the specimens showed defect union. The defect centre was still occupied by a ceramic core. CLINICAL SIGNIFICANCE: Bone and bone marrow augmented beta-tricalcium phosphate composites may qualify as a promising alternative to autograft bone for mandibular reconstruction in human and veterinary medicine.

Imaging of compositional gradients during in situ emulsification using X-ray micro-tomography.

The rate of emulsification in surfactant/oil/water systems is influenced by transport of chemicals and mixing of the fluid phases. In porous media applications, complex flow regimes are generated due to three-dimensional connectivity and irregular cross-sections of the pores facilitating the mixing for emulsification. The properties of the resulting emulsified phase depend on the interplay of flow, mixing and emulsification kinetics of the surfactant/oil/water system. Emulsification can be relatively quick. Direct visualization of the process and compositional gradients in three-dimensional pore space during flow requires imaging at few seconds time intervals. In this study, a flow unit was integrated in a synchrotron beamline-based fast X-ray computed micro-tomography set-up. Non-destructive three-dimensional visualization of multi phase flow inside a porous rock at flow conditions became viable. An oil saturated rock sample was first flooded with water, followed by surfactant solution to mobilize the remaining oil by miscible displacement. The sample was continuously imaged during injection; the scans were made at time intervals of 7-60 s. The presence of an emulsified phase in addition to the oil and the aqueous phases required a more advanced image processing workflow compared to the workflows used for the immiscible fluid systems. A newly developed image processing technique was adopted; the grey levels in the images were correlated with the local oil content in the emulsified fluid regions. The visual extractions of the pore space showed that the emulsification occurred within seconds. Compositional gradients were observed in the emulsified phase as the injected surfactant solution reached the remote locations in the pore space. While a significant fraction of the oil was displaced within few seconds, the compositional gradients persisted over several millimeter length for several minutes, illustrating a sequence of mobilization and solubilization of the oil phase. The ability to interpret such compositional gradients in real time in porous space brings capability to study interfacial phenomena in applications where in situ emulsification occurs under flow.

Anatomical characteristics of maxillary sinus septa visualized by cone beam computed tomography.

Proper implant positioning in the posterior region of the edentulous maxilla commonly requires sinus floor elevation. Maxillary sinus septa increase the risk of membrane perforation during sinus floor elevation. The purpose of this retrospective, cone beam computed tomography (CBCT)-based study was to examine the frequency, number, location, and orientation of antral septa in the maxillary sinus. Further, possible associated factors were assessed. Measurements were performed on CBCT scans of 301 patients (602 sinuses). The data were analysed statistically with respect to patient age, sex, and dentition type. One or more septa were detected in 117 patients (38.9%). A total of 188 septa were found in the 602 sinuses (31.2%). Septa were most often coronally oriented (53.2%), followed by sagittal (24.5%) and transverse (22.3%) orientations. Septa were most often found in the region of the first and second molar (37.2%), followed by the posterior region of the third molar (33.0%) and the anterior region of the premolars and canines (29.8%). A significant association was found between edentulism and the presence of septa. For edentulous patients, the septa were most often transversally oriented. Maxillary sinus septa are encountered in every third patient. This may have an influence on the performance of sinus floor elevation.

Sentinel lymph node biopsy for early stage tongue cancer-a 14-year single-centre experience.

This study was performed to report the usage of sentinel lymph node biopsy (SLNB) in clinical stage I or II tongue cancer patients with cN0 necks seen over a 14-year period. Data were collected prospectively, and a retrospective analysis was performed of 41 patients with early stage oral squamous cell carcinoma of the tongue and a cN0 neck. Sentinel lymph node (SLN)-positive patients underwent elective neck dissection, whereas SLN-negative patients were kept under careful observation. Seven of the 41 (17%) patients enrolled in the study were found to have occult metastases. The patients were followed up for a mean duration of 92 months (range 60-144 months). The neck recurrence rate for SLN-positive patients was 0% and for SLN-negative patients was 3%. The authors recommend the routine use of SLNB in patients with early stage oral squamous cell carcinoma of the tongue and a cN0 neck. Furthermore, special focus should be placed on isolated tumour cells, as their presence is of high clinical relevance.

The influence of lymph node ratio on survival and disease recurrence in squamous cell carcinoma of the tongue.

This study was performed to report the outcomes of patients with oral squamous cell carcinoma (OSCC) of the tongue over a 10-year period with the aim of testing the hypothesis that the lymph node ratio (LNR) has a significant influence on loco-regional recurrence. The charts of 227 patients with OSCC of the mobile tongue treated at the University Hospital of Zurich from 2003 to 2012 were screened. Following the application of the exclusion criteria (prior chemotherapy, radiotherapy, or surgery, perioperative death, N3 disease, unresectable disease, synchronous second primary, no signed informed consent, and follow-up <3years), prospective data were collected and a retrospective analysis performed for 88 of these patients who were treated with selective neck dissection. During a mean follow-up period of 78 months (standard deviation 37 months), loco-regional recurrence was diagnosed in 25 patients (28%). The overall and disease-specific survival rates for the study population were 72% and 80%, respectively. Perineural invasion was identified as an independent risk factor for decreased disease-specific survival, whereas LNR was not. LNR did not show an influence on disease recurrence. Thus, its prognostic value in patients with tongue cancer remains uncertain and the decision regarding adjuvant therapy should not be made solely on the basis of LNR.

Cone beam CT imaging of airgun injuries to the craniomaxillofacial region.

In airgun injuries, the removal of the projectile is often recommended. The material properties of airgun projectiles make it difficult to determine their precise anatomical location using conventional radiological techniques. Conventional X-rays give only a two-dimensional representation of projectiles and do not allow a foreign object to be located precisely. Multi-slice computed tomography (CT) has become a standard tool in diagnosis. Metal objects can cause artefacts in CT scans and make it difficult to identify adjacent anatomical structures. By contrast, cone-beam CT (CBCT) provides three-dimensional images largely free from metal artefacts. The authors present three cases of airgun injuries and discuss the diagnostic and treatment approaches used. CBCT has proved to be a useful diagnostic tool in planning the treatment of craniofacial airgun injuries. It is superior to CT in detecting hard-tissue structural damage in the immediate vicinity of high-density metal projectiles.

Complication rate in mandibular angle fractures-one vs. two plates: a 12-year retrospective analysis.

PURPOSE: Treatment of mandibular angle fractures using one or two osteosynthesis plates is still a controversial topic. Fracture, treatment, and patient-dependent influencing factors could affect the overall outcome. In the present retrospective study, complication rates of mandibular angle fractures treated by open reduction were assessed according to type of treatment. MATERIALS AND METHODS: We analyzed retrospective medical records using the search terms "mandibular angle fracture." We included all patients presenting with a mandibular angle fracture treated by open reduction and internal fixation at our department between 2002 and 2012. RESULTS: We included 186 patients treated with open reduction and miniplate fixation (84 one plate; 102 two plates). The early complication rate was significantly higher for the double-plate group (72.5% vs. 47.6%, respectively; p = 0.001). Most common findings in the postoperative period were transient hypoesthesia and tissue swelling. In the two-plate group, a significantly increased operation time of 183 min versus 150 min in the one-plate group was found (p < 0.001). Late complications did not differ significantly between both groups (21.4% single-plate group; 30.4% two-plate fixation group; p = 0.32). CONCLUSION: We found a significantly increased early complication rate in the two-plate group. Long-term complications did not differ between both groups.

Total virtual workflow in CAD-CAM bony reconstruction with a single step free fibular graft and immediate dental implants.

The Surgical reconstruction of defects of the face is challenging. Local and regional flaps have an important part to play, but large defects of bone and soft tissue are a greater problem. Microvascular tissue transfer has become the standard for such patients, and preoperative planning of bony reconstructions is now common. To use these preplanning tools best the implants should be placed in the prosthetically ideal place, and the bone positioned to surround the implants - that is, truly backward planning of the position of the bone. The buccolingual angulation and the actual position of the implants during operation can be difficult to verify. Using commonly available software and 3-dimensional printing solutions, therefore, we have constructed an algorithm to optimise the position of these implants during the operation, and to get their position as close to the planned outcome as possible. This algorithm is adaptable to any implant system and is potentially possible in any implant or preplanning software unit.

Patient-specific biodegradable implant in pediatric craniofacial surgery.

Surgical correction of premature fusion of calvarial sutures involving the fronto-orbital region can be challenging due to the demanding three-dimensional (3D) anatomy. If fronto-orbital advancement (FOA) is necessary, surgery is typically performed using resorbable plates and screws that are bent manually intraoperatively. A new approach using individually manufactured resorbable implants (KLS Martin Group, Tuttlingen, Germany) is presented in the current paper. Preoperative CT scan data were processed in iPlan (ver. 3.0.5; Brainlab, Feldkirchen, Germany) to generate a 3D reconstruction. Virtual osteotomies and simulation of the ideal outer contour with reassembled bony segments were performed. Digital planning was transferred with a cutting guide, and an individually manufactured resorbable implant was used for rigid fixation. A resorbable patient-specific implant (Resorb X-PSI) allows precise surgery for FOA in craniosynostosis using a complete digital workflow and should be considered superior to manually bent resorbable plates.

Double-blind, randomized, placebo-controlled study to evaluate the effects of tegaserod on gastric motor, sensory and myoelectric function in healthy volunteers.

BACKGROUND: The effects of tegaserod on gastric accommodation and postprandial satiety remain unclear. AIM: To compare the effects of tegaserod 6 mg twice daily vs. placebo on gastric volumes, postprandial symptoms, gastric emptying, small bowel transit and the surface electrogastrogram in female and male healthy volunteers. METHODS: Randomized, double-blind, placebo-controlled study evaluated gastric function before and after 7 days of tegaserod 6 mg twice daily (n = 21) vs. placebo (n = 20) in healthy volunteers. Validated methods were used to study gastric emptying, myoelectrical activity, volumes and satiation postnutrient challenge. RESULTS: There were no significant effects of tegaserod on the primary endpoints assessing gastric function: emptying of solids or liquids, total gastric volumes or myoelectrical activity. Maximum tolerated volume and aggregate symptom score with nutrient challenge on placebo were 1,035 mL (+/-44) and 130 (+/-15) vs. 989 mL (+/-43) and 117 (+/-15) during tegaserod, respectively (all P = N.S.). Postprandial change in proximal gastric volume by single photon emission-computed tomography was decreased in females on tegaserod (246 +/- 30) vs. placebo (358 +/- 32) (P = 0.015). Proximal fasting volumes in females were increased on tegaserod (126 +/- 12) vs. placebo (92 +/- 13) (P = 0.066). CONCLUSIONS: While tegaserod decreased proximal gastric volume change after a meal, it does not appear to have significant effects on gastric motor and sensory function in healthy individuals. Further studies are required in patients with disturbances of gastric motor and sensory function.

Dentofacial rehabilitation by osteodistraction, augmentation and implantation despite osteogenesis imperfecta.

Osteogenesis imperfecta-- a heritable systemic disorder characterized by enhanced bone fragility-- is frequently associated with a Class III malocclusion and distinct dental disorders. This patient, suffering from a late form of osteogenesis imperfecta, displayed early loss of teeth and severe maxillary hypoplasia. Bone grafting of the alveolar ridge was assumed not to guarantee a neutral basal relation before dental implantation. Due to the risk of atypical fractures conventional orthognathic surgery was excluded in the atrophic maxilla. In contrast to a conventional Le Fort I osteotomy, osteodistraction of the maxilla can be performed omitting the precarious down-fracture procedure. Despite a lack of reports on this technique in patients with osteogenesis imperfecta, dysgnathia was corrected by osteodistraction of the upper jaw. The loss of teeth was treated by augmentation of the alveolar crest using autogenous bone from the iliac crest followed by placement of dental implants. Stable normocclusion of the implant-supported overdentures was achieved without any detectable relapse over 4 years. For the first time it has been demonstrated that advanced surgical techniques like osteodistraction, alveolar crest augmentation and dental implantation can successfully be combined for dentofacial rehabilitation even in patients suffering from osteogenesis imperfecta.

Aerophagia in adults: a comparison with functional dyspepsia.

BACKGROUND: Aerophagia is a functional upper gastrointestinal disorder that has not previously been well described in a large patient group. AIMS: To describe the initial evaluation of patients who presented with symptoms of aerophagia at a tertiary medical centre. METHODS: A computerized search was used to identify all patients who were diagnosed with aerophagia at the Mayo Clinic, Rochester between 1996 and 2003 (n = 79). Individual medical charts were abstracted for information on the demographics, clinical features, co-morbid diagnoses, diagnostic workup and treatment. Information on presenting symptoms was also collected for a group of patients who were classified as having functional dyspepsia for comparison (n = 121). RESULTS: The median duration of symptoms in patients with aerophagia was 24 months. The most common symptoms were belching (56%), abdominal pain (19%), bloating (27%) and abdominal distension (19%). Patients with functional dyspepsia had a higher prevalence of reporting nausea, vomiting, early satiety, weight loss and abdominal pain (all P < 0.01, adjusting for age, gender and body mass index). Significantly more patients with aerophagia had anxiety (19%) than those with functional dyspepsia (6%, P < 0.01). CONCLUSIONS: Individuals with aerophagia experience prolonged upper gastrointestinal symptoms. Initial presenting symptoms appear to be distinctly different from those who have functional dyspepsia.